Wrath of The Lich King
LK was such an amazing villain, I remember seeing ICC for the first time and it was so epic. Probably because it felt like "this is it, this is where you defeat the Lich King, this is what everything has been leading up to."
He had a great story, and I personally was satisfied but at the same time like "wtf O_o" at the ending cinematic. It was disturbing and chilling but at the same time quite epic (for lack of a better word) and I thought it wrapped things up well enough (better than Cata, at least...). I do want to see what is happening with the scourge and Bolvar, though. There are still a few loose ends in wotlk.
Great story nevertheless ^_^